196 



PROCEEDINGS OE THE GEOLOGICAL SOCIETY. 



formation in that area. In no other district do we find evidence to 

 account for such loss, or beds that can be correlated with those of the 

 south of Ireland. Mr. Hull tabulates the succession of the Carboni- 

 ferous and Devonian rocks of North Devon and the south of Ireland, 

 and endeavours to show their relation and probable contempo- 

 raneity as follows* : — 



The above table is probably the true reading of the areas under 

 notice. This table is followed by a concise description of the North- 

 Devon formations and their fossils, in descending order, from the 

 Carboniferous series south of Barnstaple to the Foreland grits. It 

 is worthy of attentive study ; and Mr. Hull has marked with an 

 asterisk the identification by Mr. Baily of those species also occurring 

 in the Carboniferous and Coomhola beds of the south of Ireland, 

 thus showing still further, on palseontological grounds, the rela- 

 tionship between the now separated, but probably once united, 

 areas. 



Mr. Hull's views " that the missing chapter between the Silurian 

 and the Carboniferous, in the palacontological history of Ireland, is 

 supplied by the rocks of Devonshire with their marine organisms " is 

 probably near the truth ; and the proportions assumed in the geolo- 

 gical series by the Devonian rocks " offers a solution to one of the 

 problems of Irish geology." 



Professor Hull enters into geographical considerations of a minute 

 character, to which I must refer, and which bear significantly upon 

 the relative changes of sea and land from the Silurian to the close of 

 the Carboniferous period. The successive phases of the physical 

 conditions are given through four diagrams of the British Islands on 

 plate v., which show the relations of land and sea, or elevation and 

 depression. 



He believes that there is only one true Old Red Sandstone in North 

 Devon, which is represented by the Pickwell-Down Sandstone, and 

 that the Upper Old Eed of Scotland and Ireland is not the equivalent 

 of the Devonshire marine Devonian strata, which are newer and 



North Devon. South of Ireland. 



( Earthy limestones, with Posidono- Carboniferous limestone. 



• Hfracombe limestone group. | Strata absent over the area 

 I Hangman grits (Martinhoe beds), f in the south of Ireland. 



j^in-un oiiciieo anu. ±111100 bunco. 



Foreland grits (base invisible). Glengariff beds, passing 



down into the Upper 

 Silurian beds. 



* Hull, loo. cit p. "144. 



